Computer-scaler



c. W. REED 3,413,450

COMPUTER- SCALER 1. Filed Sept. l2 1961 2- Sheets-Sheet l Nov. 26, 1968Origina Nov. 26, 1968 C. W. REED COMPUTER-SCALER Original Filed Sept.l2, 1961 PULSES MECHANICAL CAIIQV PULS: CvuMTErIi 2 Sheets-Sheet 2 ioahvCDRRV PULSES To CAQQV COUNTER .wodf' CA QRY PULSES TO CAR EY COUNTER`SCRLE DDWN CUNTER r -a--NCOMN PULSFS INV EN TOR.

United States Patent O 3,413,450 COMPUTER-SCALER Clifton W. Reed, 5016Calvin Ave., Tarzana, Calif. 91356 Continuation of application Ser. No.137,572, Sept. 12, 1961. This application Mar. 25, 1965, Ser. No.454,230 Claims. (Cl. 23S-92) ABSTRACT 0F THE DISCLOSURE Acomputer-Scaler is provided for numerically displaying a quotient orratio resulting from the division of a total number of pulses counted ina dividend count channel divided by a total number of pulses counted ina divisor count channel. The dividend and divisor count channels eachinclude input terminals for receiving independent trains of pulses theratio of which is to be determined. These trains of pulses may be ofunknown frequencies which frequencies themselves may be either periodicor aperiodic. The divisor count channel includes means for generating anelectrical control pulse in response to a predetermined accumulatedpulse count constituting an integral multiple of n where n is anypositive integer. The dividend count channel includes means forgenerating an electrical carry pulse in response to each Nth count orpulse received where N is a preselected integer equal to the saidintegral multiple. A digital carry pulse counter is included forcounting the carry pulses and this carry pulse counter is terminated inresponse to generation of the control pulse from the divisor counter.The count displayed by the carry pulse counter upon termination is thenequal to the quotient of the two trains of pulses times the factor 10U.A decimal position may be indicated in accord with the value of n sothat the carry pulse counter reads directly the ratio. In addition, astorage means may be provided in the divisor count channel for defininga time interval corresponding to the total time lapse necessary toaccumulate the predetermined total pulse count in theY divisor counterand this storage means may then operate at a subsequent time to startand terminate the counting by the dividend count channel such thata-gain the displayed count by the carry pulse counter will indicate thedesired ratio but wherein the two trains of pulses need not occursimultaneously.

This application is a continuation of my copending application, Ser. No.137,572, iiled Sept. 12, 1961, for Computer-Scaler.

This invention deals generally with electronic counters and, moreparticularly, with a direct readout computerscaler for computing anddisplaying quotients of pulse counts, pulse frequencies or countingrates, and percentage ratios of unknown frequencies to standard orreference frequencies.

Various types of computer-scalers are known to the art. One existingtype of instrument, for example, is equipped with pulse counting meansfor developing the two counts whose quotient is desired and a separatecomputer which performs an electrical mathematical division operation toobtain the desired quotient. Instruments of this type are excessivelycomplex and costly.

The complexity and cost of these instruments are avoided in another typeof computer-sealer which is commonly employed in high frequency countingrate applications. This latter type of instrument is equipped with adecade counter and an accurate time interval generator which is capableof yielding accurate, even decade time base or counting time intervals,such as 10"3 second, 10"2 second, 10-1 second, l second, and 10 secondintervals. These even decade time intervals make it possible to read outthe counting rate directly from the counting channel decades so thatcomputation by an external computer is unnecessary. That is to say,since the elapsed time of the pulse count or counting interval with aninstrument of this type is always an even decade interval, the totalcount displayed by the instrument is obviously the numerical value ofthe counting rate. The only additional'step necessary to obtain thecounting rate itself is to properly indi.- cate the decimal point, whichcan be easily done because of the even decade counting intervalemployed.

Computer-scalers of this latter type, however, are not satisfactory formany counting applications. In the nuclear field, for example, thedesire to work with activities as low as practical and the random natureof emissions of radioactive sources require relatively long countingintervals in order to obtain reasonable counting accuracy. Rarely aremeasurements made in less than 1 second in the nuclear iield and, inmost cases, the counting interval is more than l0 seconds.

In the nuclear iield, therefore, as Well as in other iields in whichrelatively long counting periods are required for reasonable countingaccuracy, it is desirable to have available a computer-Scaler which iscapable of displaying directly the counting rate for a counting intervalwhich is longer than 1 second and, in the great majority of cases,longer than 10 seconds. It is obvious, of course, that if an even decadecounting interval is selected, such as 1 second, 10 seconds, 100seconds, or 1,000 seconds, the direct reading even decadecomputer-sealer mentioned above could be used. From a practical point ofview, however, the time interval steps between these even decadeintervals are too long in terms of practical measuring time. That is tosay, in many counting applications, a counting interval of l0 Seconds or100 seconds may be too short to obtain a reasonable counting accuracy,while the next counting intervals which can be employed in the existingequipment, namely, seconds or 1,000 seconds, may be too long because ofthe limitation they place on the number of samples or measurements thatcan be handled during a normal Work period. The optimum countinginterval might be 30 seconds or 30() seconds, for instance. Suchcounting intervals cannot be employed in the existing direct readingcomputer-Sealers. For this reason, up to the present time, it has beenimpractical to employ a decimal time basis as a means of obtainingcounting rate readouts of low frequency inputs.

This invention provides a new and unique computer- Scaler whichfurnishes a direct readout countering rate or frequency display forpreset counting time intervals other than fixed even decade intervals.These preset counting intervals may correspond, for instance, to unitsteps in a decimal counting system, binary steps in a binary countingsystem, or corresponding steps in any other counting system. In oneillustrative form of the invention, for example, decimal time intervalsteps of 1 through 9 with any one of the decimal multipliers 100, 101,102, l03 and 104 can be selected to give pre'set counting time baseintervals of 1 second, 2 seconds, 3 seconds, 9 seconds times any one ofthe decimal multipliers. In another illustrative form of the invention,binary time interval steps of 1 second, 2 seconds, 4 seconds, 8 seconds,16 seconds times any one of the decimal multipliers can be selected.

While the discussion thus far has related only to the computation anddisplay of counting rates or frequencies, i.e., quotient computations inwhich the divisor count equals units of time which are derived from atime interval generator or other timing mechanism, the presentinstrument is cable of computing and displaying quotients of two pulsecounts where the pulses are derived from any sources. When thecomputation is other than a frequency or count rate computation, theinstrument is operated on a preset divisor count basis rather than apreset time basis.

In this case, the instrument furnishes a direct readout quotient displayfor preset divisor count steps other than fixed even decade steps whichmay correspond to unit steps in a decimal system, binary steps in abinary system, or to corresponding steps in any other counting system asdiscussed above in connection with counting rate or frequencycomputations. The instrument can also be used for ratio counting inwhich an unknown count rate may be read out directly as a percent of areference or standard frequency.

It should be pointed out here that the expression pulse as used hereinis intended to encompass not only distinct electrical pulses accordingto the more commonly accepted definition of the expression but also thepeaks of a continuous wave form signal, such as a sine wave signal, aswell. Accordingly, the expression pulse counter as used herein is meantto cover an instrument for counting both the distinct pulses in a pulsetrain and the peaks of a continuous wave form signal.

With this preliminary discussion in mind, a general object of thepresent invention may be stated as being to provide a new and uniquedirect readout computer-Scaler for computing and displaying the quotientof pulse counts, counting rates or frequencies, and frequency ratios.

A more specific object of the invention is to provide a direct readoutcomputer-Scaler of the character described which employs a presetdivisor count or time base that may be other than an even decade countoir interval.

Another object of the invention is to provide a direct readoutcomputer-Scaler of the character described which can be designed toutilize a decimal counting system, a binary counting system, or any ofthe other known counting systems.

A further object of the invention is to provide a computer-sealer of thecharacter described which is especially suitable for electronic andnucleouic count rate or frequency measurements which require medium tolong time base intervals.

Yet a further object of the invention is to provide a direct readoutcomputer-Scaler of the character described in which the decimal point isautomatically indicated in the quotient, frequency, or ratio display ofthe instrument.

A still further object of the invention is to provide a direct readoutcomputer-sealer of the character described which is relatively simple inconstruction, inexpensive to manufacture, compact, and otherwise ideallysuited to its intended purposes.

Other objects, advantages, and features of the invention will becomereadily apparent as the description proceeds.

Briey, the objects of the invention are attained by providing acomputer-scaler equipped with two separate count channels. One of thesechannels, hereinafter referred to as the divisor count channel, developsthe count which is the divisor of the quotient, frequency, or ratiodisplayed by the instrument. The other channel, hereinafter referred toas the dividend count channel, develops the count which is the dividendof the display.

The divisor count channel includes a counter, which may be a digitalpulse counter where the measurement to be made is the quotient of twopulse counts or the ratio of two frequencies, or a timer where themeasurement to be made is a frequency or counting rate determination,with means for displaying the accumulated pulse count or expired time.The dividend count channel includes a digital scaledown pulse counterwith means for developing a carry pulse in response to each Nth count ofthe latter counter, where N is a scaledown factor equaling a preselectedinteger, and a digital carry pulse counter for counting and displayingthe total number of carry pulses developed by the scaledown counter.

During operation of the instrument to make a quotient determination, theincoming pulses from which the dividend count is derived are fed to thedividend count channel and the incoming pulses from which the divisorcount is derived are fed to the divisor count channel. The scaledowncounter develops a carry pulse in response to each Nth count and thecarry pulses are counted in the carry counter which continuouslydisplays the accumulated carry pulse count. The count is terminated whenthe scaledown factor N is in the ratio of l()n to the accumulated pulsecount in the divisor channel counter, where n is an integer, which, inthe broad concept of the invention, may be any plus or minus integer. Atthe end of the counting interval, the total accumulated pulse count C1in the dividend count channel is C1=R +I' where R is the reading of thecarry counter and r is the count remaining in the scaledown counter atthe end of the counting interval. The quotient Q of the totalaccumulated pulse count in the dividend channel over the accumulatedpulse count C2 in the divisor count channel is then Q Q1 R XN -I-'rnC'z- C2 Since, as already noted, the scaledown factor N is in the ratioof 10n to the accumulated pulse count in the divisor channel counter,i.e., N/ C2210, the above equation becomes 7. Q-RXIO +62 In other words,if the count is terminated when the dividend scaledown facto-r is in theratio of an integer power of 10 to the total accumulated divisor count,the accumulated carry pulse count R displayed by the carry counter atthe end of the counting interval will be numerically equal to thequotient of the total accumulated pulse count in the dividend countchannel over the accumulated pulse count in the divisor channel counterwith an error equal to 1'/ C2. This error is maximum, for any givenaccumulated divisor count C2, when the remainder count r is 1 less thanN, the number of counts necessary in the scaledown counter to develop acarry pulse. As the accumulated divisor count C2 increases, of course,the error r/ C2 approaches zero and, if the divisor count C2 issufficiently large, the error can be neglected. In this case,

so that the carry count displayed by the carry counter can be taken toindicate the numerical value of the quotient Q. All that is thennecessary to obtain the decimal value of the quotient is to properly setoit the decimal point, the position of which is xed by the power n whichis known. In the illustrative embodiment of the invention, the positionof the decimal point is indicated automatically in the quotient displayof the carry counter by means of a light in the display.

When making a frequency or counting rate measurement with theinstrument, the divisor count C2 equals units of time, such as seconds,obtained from a timer in the divisor count channel. In a simple form ofthe present instrument, this timer may comprise a time clock to be readby the operator of the instrument. In the more sophisticated,illustrative embodiments of the instrument, the timer consists of a timeinterval generator for generating timing pulses at predetermined timeintervals, such as .1 second intervals, and a digital counter forcounting and displaying the total number of `timing pulses generated bythe time interval generator. The illustrative embodiments of the presentinstrument are also equipped with means for presetting diferentpreselected divisor counts or time base intervals into the divisor countchannel and terminating the count automatically in response in theaccumulation of the preset count or time interval in the divisor channeland with means for presetting an appropriate scaledown factor in thescaledown counter of the dividend count channel such that the carrycounter will display the correct quotient of the dividend and divisorchannel counts or the correct counting rate or frequency when countingis terminated.

A unique feature of the illustrative embodiments of the inventionresides in the fact that the divisor count, like the dividend count, isscaled down by a preset scaledown factor equal to the scaledown factorin the dividend count channel. This is accomplished by means of ascaledown counter into which the scaledown factor is presetsimultaneously with presetting of the scaledown factor into the`scaledown counter of the dividend count channel. The carry pulsesdeveloped by the divisor channel scaledown -counter are counted andtheir accumulated number is displayed by a carry pulse counter in thedivisor channel. As will be seen, this greatly simplifies the equipment.

When the instrument is used for ratio counting, i.e., determining theratio of an unknown frequency to a standard reference frequency, theunkown frequency f1 is fed to the dividend count channel and thestandard or reference frequency f2 is fed to the divisor count channel.The count is stopped at a present accumulated count in the divisor countchannel. The unknown frequency f1 is equal to the total accumulateddividend channel count C1 divided by the elapsed time T of themeasurement and the standard frequency f2 is equal to the totalaccumulated divisor channel count C2 divided by the elapsed time T ofthe measurement. Since the elapsed time of measurement is the same forboth channels, the frequency ratio f1/f2 is agi/La f2 Cz/T C2 Now, theytotal accumulated dividend channel count equals the reading R of thedividend channel carry counter times the present scaledown factor N inthe dividend channel scaledown. If the count is terminated when thescaledown factor N is in the ratio of l()n to the total accumulateddivisor channel count C2 and any remaining count in the dividend channelscaledown counter is neglected, as before the above equation becomes Inother words, the reading of the scaledown counter will be the numericalvalue of the frequency ratio. The percentage value of the ratio isobtained by simply setting off the decimal point, the position of whichis xed by the known power n and is indicated automatically in theinstrument.

The above method of ratio counting requires that both frequencies beavailable at the same time. In some situations, however, only onefrequency may be available at a time. In this case, the known frequencyis counted rst inthe dividend channel and the elapsed -time to reach apreset count is noted. The unknown frequency is then counted in thedividend channel for the same length of time and with a scaledown factorpreset in the dividend channel scaledown counter which is in the ratioof l0n to `the preset known frequency count. Here, again, then, thereading of the dividend channel carry counter at the end of the unknownfrequency count is numerically equal to the ratio of the twofrequencies. The decimal point is indicated automatically as before.

In the foregoing discussion, the remainder count in the dividend channelscaledown counter has been neglected. However, the remainder count canbe taken into account to obtain as accurate a measurement as desired byuse of a table relating the remainder count to the particular scaledownfactor used to obtain additional decimal places. Electricalinterpretation is also possible by means of a simple matrix for relatingthe scaledown factor to ythe remainder count.

The illustrative embodiments of the invention will now be described indetail by reference to the attached drawings, wherein:

FIG. 1 diagrammatically illustrates one form of the present instrumentwhich uses decade counters in the dividend and divisor count channelsand operates on a decimal counting system;

FIG. 2 diagrammatically illustrates one type of time interval generatorwhich can be used in the instrument;

FIG. 3 diagrammatically illustrates simplified binary scaledown counterswhich can be used in the instrument in place of the decade scaledowncounters in FIG. l; and

FIG. 4 diagrammatically illustrates the use of a mechanical carrycounter with an electronic scaledown counter to obtain anelectromechanic, direct readout computer- Scaler.

Reference is made first to the decimal system instrument illustrated inFIGS. l and 2 of these drawings, wherein numeral 20 denotes the dividendcount channel and numeral 22 the divisor count channel of theinstrument. During operation of the instrument, the electrical pulses 24from which is to be derived the dividend count for the quotient or ratiodetermination made by the instrument are delivered to the dividend countchannel 20. The electrical pulses 26 from which is to be derived thedivisor count for the determination are delivered to the divisor countchannel 22. As noted earlier, these electrical pulses may consist ofdiscrete pulses, such as square wave pulses, for example, according tothe more cornmonly accepted definition of the term pulse, or they maycomprise the peaks of a continuous wave form signal, such as a sine wavesignal. Also, these pulses may be derived from any desired externalsources. When making a counting rate or frequency determination,however, pulses 26 which are delivered to the divisor channel 22 arederived from a time interval generator 28 in the divisor channel 22 andcomprise timing pulses which `occur at predetermined time intervals,such as .l second intervals.

Dividend count channel 20 includes an input gate or switch 29 throughwhich the pulses 24 enter the dividend channel. During operation of theinstrument, this gate is opened, to terminate counting in the dividendchannel, in response to a predetermined accumulated pulse count in thedivisor count channel 22.

Input gate 29 feeds a `digital pulse counter 30, which is hereinafterreferred to as a scaledown counter for reasons which will becomeapparent as the description proceeds. This scaledown counter maycomprise any one of several different types of conventional digitalcounters with means for developing a control pulse capable of actuatinga following counter in response to each Nth count of the scaledowncounter, where N is a presettable scaledown factor which can be selectedfrom a series of preselected integers. The preset decade counterdescribed in the manual entitled Instruction Manual Moder lO'lA PresetDecade Counting Unit distributed by Computer-Measurements Company, ofSylmar, Calif., is such a counter. For convenience, scaledown counter 30has been illustrated as being of the type disclosed in this manual.

As described more fully in the manual, counter 30` comprises a decadecounting unit 30a with a presettable selector switch 30b having tenpositions associated With the integers 0 through 9, respectively, and areset pulse generator 30C. In operation, decade counting unit 30a sensesthe number of electrical pulses fed to its input and `displays the countof pulses received on an illuminated scale 30d. This display scaleconsists of the integers 0f through 9 ywhich are consecutivelyilluminated in response to consecutive counts of the counting unit 30a.Counting unit 30a also compares the input pulse count With the integerassociated with the preset position of the selector switch 3611 and,when the pulse count and preset integer coincide, the counting unitdelivers a coincidence pulse to the reset pulse generator 30C, asindicated. This generator is triggered by and develops a reset pulse inresponse to each coincidence pulse. Each reset pulse, in turn, isdelivered back to the `decade counting unit 30111 and resets the latterback to zero, after which counting starts anew in the counting unit.Thus, for example, if the selector switch 30h is preset to the positionassociated with the integer 6l, decade counting unit 30a counts up to 6and then rests to zero, after which the counting unit again counts to 6and again resets, and so forth. If the selector switch is preset to theposition associated with integer 3, the counting unit 30a counts to 3and resets. In this invention, the integers through 9 which areassociated with the positions of selector switch 30b are the scaledownfactors N and switch 30b is a scaledown factor selector switch.

According to this invention, the reset pulses developed by the resetpulse generator 30C are also `delivered to the input of a second digitalcounter 32 in the dividend count channel 20. Digital counter 32 maycomprise any conventional digital counter capable of counting anddisplaying the reset pulses developed by the reset pulse generator 30C.For illustrative purposes, digital counter 32 has been illustrated ascomprising a decade counter including a units decade 32a, a l0s decade3212, a l00s decade 32e, a 1,000s decade 32d, and a 10,000s decade 32e.Each decade has a display scale 321 like that described in connectionwith the counting unit 30a. For reasons which will become evident as thedescription proceeds, the reset pulses which are delivered by thescaledown counter 30 to the decade counter 32 are hereinafter referredto as carry pulses and the counter 32 is referred to as a carry pulsecounter. Carry pulse counter 32, then, counts and displays the totalnumber of carry pulses developed by the scaledown counter 30.

Between the decades of the carry counter 32 are small lamps 34a, 3411,34C, 34d and 34e. As will shortly be described, these lamps areselectively illuminated during operation of the instrument to indicatethe position of the decimal point in the carry pulse count displayed bythe counter 32.

Divisor count channel 22 is generally similar to the dividend countchannel in that the divisor count channel includes an input switch orgate 36 through which the pulses 26 enter the latter channel, a digitalscaledown pulse counter 38 identical to the scaledown counter 30 forcounting the incoming pulses 26 and developing a carry pulse in responseto each Nth count of the scaledown counter, where N is the integer orscaledown factor associated with the preset position of the scaledownfactor selector switch 38b of the counter 38, and a digital carry pulsecounter 40, including counting decades 40a, 40h, 40e and 40d forcounting and displaying the total number of carry pulses developed bythe scaledown counter 38. Each decade 40a, 40b, 40C and 40d includes adisplay scale 40e for displaying the current count in the decade. Timeinterval generator 28 in the divisor count channel 22 is located aheadof the divisor channel gate 36. A switch 42 is provided for selectivelyconnecting the input of the gate 36 to the time interval generator 28 orto a second input terminal 44 through which pulses from an externalsource may be delivered to the divisor count channel 22.

Indicated at 46 is a selector knob for simultaneously presetting thescaledown factor selector switches 30b and 38b of the scaledown counters30 and 38. Selector knob 46 has ten positions identified by the integers0 through 9, respectively, and is operatively connected with theselector switches 30b and 38!) through linkage 48. This linkage isarranged in such a way that turning of the selector knob 46 to anyselected one of its ten positions simultaneously turns the scaledownfactor selector switches 30b and 38h to the positions associated withthe scaledown factor which is numerically the same as the integeridentifying the selected position of knob 46. Thus, if the selector knob46 is turned to the position identified by integer 7, selector switches30b and 38h are simultaneously turned to the positions associated withscaledown factor 7.

During operation of the divisor channel carry pulse counter 40, eachdecade 40a, 40h, 40e and 40d of the counter counts up to 9 and thenresets to zero. As each decade resets, it develops a carry pulse Whichis delivered to and advances by one the following decade, in thewell-known way. The carry pulses developed by the divisor scaledowncounter 38 and by the decades 40a, 40h, 40C and 40d are utilized to openthe input gates 29 and 36 and thereby terminate counting in the dividendand divisor count channels. This is accomplished as follows: Indicatedat 50 is a selector knob having positions identified by the decimalmultipliers l, 10, 100, 1,000 and 10,000, respectively, as shown.Operated by this selector' knob is a selector switch 52 having contacts52a, 521), 52C, 52d and 52e which are electrically connected throughleads 54a, 54b, 54C, 54d and 54e, respectively, to the outputs of thescaledown counter 38 and the decades 40a, 40h, 40C and 40d,respectively. Selector switch 52 further includes a rotatable contact527, fixed to the shaft 56 of the selector knob 50, which engagescontact 52a when the selector knob 50 occupies the position identifiedby the decimal multiplier 1, Contact 52b when the selector knob S0occupies the position identified by the decimal multiplier 10, contact52C when the selector knob occupies the position identified by thedecimal multiplier 100, Contact 52d when the selector knob occupies theposition identified by the decimal multiplier 1,000, and contact 52ewhen the selector knob occupies the position identified by the decimalmultiplier 10,000. Switch contact 52]c is electrically connected withthe input gates 29 and 36 through leads 58 and 60. When the selectorknob 50 is turned to any one of its positions, then, the selector switchcontact 52f is rotated into engagement with the corresponding switchcontact 52a, 52]), 52C, 52d or 52e, as the case may be, and a pulse isdelivered to the gates 29 and 36, through the selector switch 52, whenthe scaledown counter or the corresponding decade 40a, 40h, 40C, 40d ofthe divisor channel carry counter resets and develops a carry pulse. Thepulse thus delivered to the input gates 29 and 36 is hereinafterreferred to as a control pulse and operates to open the gates andthereby terminate counting in both count channels. For example, if theselector knob S0 is turned to the position identified by decimalmultiplier 100, a control pulse is delivered to the input gates 29 and36 when the 5 decade 4Gb of the counter 40 resets to zero and delivers acarry pulse to the following 1,000s decade 40e. This occurs, of course,on the tenth count of the 100s decade 40b or at a total accumulatedcount of 1,000 in the divisor channel.

Indicated at 62 is a reset pulse generator, which may be like the resetpulse generator 30e, having its input connected to lead S8 through aswitch 64. When switch 64 is closed, the control pulse delivered to theinput gates 29 and 36 through the selector switch 52 is also deliveredto the reset pulse generator 62. This generator generates a reset pulsein response to the control pulse, which reset pulse is applied to thecounters 30 and 32 of the dividend channel and the counters 38 and 40 ofthe divisor channel, through leads 66, for resetting the counters toZero. Input gates 29 and 36 are of a type which remain open once theyare actuated by the control pulse delivered through the selector switch52. The reset pulses generated by the reset pulse generator 62 are alsodelivered to the input gates 29 and 36, through leads 68, and serve tore-open these gates. Gates 29 and 36 might comprise, for example,normally closed relays with holding circuits which lock the relays intheir open, energized state in response to initial energization of therelays by the control pulse delivered through the switch 52 and normallyclosed relays in the holding circuits which are energized by the resetpulse from generator 62 to break the holding circuits. Included in thereset pulse generator 62 is a manual reset switch '70. Reset pulsegenerator 62 generates a reset pulse in response to manual operation ofswitch 70, even though switch 64 is open, which reset pulse resets theseveral counters of the instrument and opens the input gates 29 and 36.

Selector knob 50 operates a second selector switch 72 having contacts72a, 72b, 72C, 72d and 72e connected to the decimal point indicatinglamps 34a, 34h, 34C, 34d and 34e, respectively, through leads 74a, 74b,74C, 74d and 74e, respectively. Included in the switch 72 is a switchcontact 72f fixed to the shaft 56 of the selector knob 50 which engagesthe contacts 72a through 72e as the selector knob 50 is turned to itsvarious positions to complete energizing circuits through the lamps 34athrough 34e. Thus, for example, when the selector knob 50 is turned tothe position identified by the decimal multiplier 1,000, selector switchcontact 72f is rotated into engagement with switch contact 72d toenergize lamp 34d.

In describing the operation of the instrument, we will rst assume thatthe quotient of two pulse counts, derived from incoming pulses 24 and 26from two external sources (not shown), is to be determined. In thiscase, the divisor count channel switch 42 is shifted to its position ofengagement with input terminal 44 of the divisor count channel so thatthe incoming pulses to the divisor count channel from the externalsource are delivered to the latter channel through the input terminal44. Scaledown counter 30 in the dividend count channel 20 counts theincoming pulses 24 and develops a carry pulse in response to each Nthcount of the counter 30, where N is the scaledown factor correspondingto the preset position of the scaledown factor selector switch 30b inthe counter. The carry pulse counter 32 in the dividend count channel,in turn, counts and displays the number of carry pulses developed by thescaledown counter 30. The accumulated carry pulse count can be read fromthe display scales 32f in the decades 32a through 32e of the carrycounter at any time. Assuming that the dark integers in the displayVscales 32]c are the illuminated integers indicating the current countin each decade, for example, the carry count reading of the carrycounter is 76451. The total accumulated pulse count C1 in the dividendcount channel is R N-{-r, where R is the reading of the carry counterand r is the remainder count indicated on the scale 30d of the scaledowncounter 30. Similarly, the scaledown counter 38 in the divisor countchannel 22 counts the incoming pulses 26 to the latter channel anddevelops a carry pulse in response to each Nth count of the scaledowncounter, where N is the scaledown factor corresponding to the presetposition of the scaledown factor selector switch 38b in the lattercounter. The carry pulse counter 4S counts and displays the number ofcarry pulses developed by the scaledown counter 38. The number of suchcarry pulses can be read from the scales 40e in the decades 40a through40d of the counter 40. As in the case of the dividend count channel, thetotal accumulated pulse count in the divisor count channel 22 is equalto the reading of the carry counter times the scaledown factor N, whichis preset in the scaledown counter 38, plus any remaining count in thelatter counter.

Now, then, the quotient Q of a total accumulated pulse count C1 in thedividend count channel 20 over a total accumulated pulse count C2 in thedivisor count channel 22 is If counting in the dividend channel 20 isterminated when the scaledown factor N which is preset in the scaledowncounter 30 is in the ratio of 10n to the total accumulated pulse countC2 in the divisor count channel 22, where u is any plus or minusinteger, the above equation becomes 7. 1 u:- Q RX C2 As preliminarilynoted, if the total accumulated pulse count C2 in the divisor countchannel is suicientiy large,

the remainder count r remaining in the dividend channel scaledowncounter 30 when counting is terminated can be neglected, in which casethe quotient Q becomes In other words, if counting is terminated whenthe preset dividend scaledown factor N is in the ratio of 10n to thetotal accumulated pulse count in the divisor count channel, where n canbe any selected plus or minus integer or power, the reading R of thedividend channel carry counter 32 is numerically equal to the quotientof the total accumulated pulse count in the dividend count channel overthe total accumulated pulse count in the divisor count channel. Ali thatis necessary to obtain the decimal value of the quotient is to properlyindicate the decimal point, the position of which is pre-established bythe -selected integer or power n.

For example, if we elect to terminate counting when the totalaccumulated pulse count inthe divisor count channel becomes 3, 30, 300,3,000 or 30,000, say 3,000 pulse counts, for example, a scaledown factorof 3 is preset into the dividend channel scaledown counter 30. Assumingthat when counting is terminated, the reading R of the dividend channelcarry counter is 76451 as indicated, the

quotient of the dividend pulse count over the divisor pulse count is 76451 X 3 3 Q- W 76451 l0 76.451

In essence, therefore, the procedure followed in the present instrumentwhen making a quotient determination of two pulse counts is, rst, selecta total accumulated count in the divisor count channel at which countingis to be terminated and preset the appropriate scaledown factor into thedividend channel scaledown counter 30, then, begin the count, and,finally, note the carry count displayed by the dividend carry counter 32when the selected accumulated count is reached in the divisor channel.Now it is evident that this procedure could be followed with aninstrument equipped with a simple indicating digital pulse counter inthe divisor channel in place of the illustrated scaledown and carrycounter arrangement by having the operator of the instrument simply notethe reading of the dividend channel counter when the preselected totalaccumulated pulse count appears in the divisor counter. It ispreferable, however, to have counting end or repeat automatically whenthe preselected total accumulated divisor pulse count is reached. Thisautomatic termination or repetition of the count could be accomplished,of course, with any digital counter equipped with means for sensing thepreselected divisor count and with means for terminating or repeatingthe count when the preselected divisor count is reached. It is alsoevident that such an automatic instrument could be provided with oneknob for presetting the scaledown factor into the scaledown counter ofthe dividend channel and another knob or knobs for presetting thepreselected total accumulated pulse count into the divisor channel. Itis preferable, however, for simplicity of operation, that when theselected count is preset in the divisor channel, the appropriatescaledown factor be simultaneously preset into the dividend channel. Theinclusion of the scaledown counter 38 in the divisor count channel 22permits this simultaneous presetting of the dividend channel scaledownfactor and divisor channel count to be simply and uniquely accomplished,as follows:

Recalling that the different scaledown factors which can be preset intothe dividend channel scaledown counter 30 of the illustrated instrumentare v0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and that for the dividend channelcarry counter 32 to indicate the numerical value of the quotient of thedividend channel count over the divisor channel count, the selectedscaledown factor and the preselected divisor count must be in the ratioof a power of 10, it is evident that the preselected divisor countswhich can be used in the instrument are equal to the above scaledownfactors times any decimal multiplier, such as 101, 102, 103, 104, and soon. Now, with the scaledown counter 38 included in the divisor countchannel 22, it is evident that when the divisor scaledown factorpresetting switch 38h of the latter counter is set to any selectedscaledown factor N, a carry pulse lwill appear at the output of thescaledown counter 38 when the accumulated pulse count in the divisorcount channel 40 equals N or N 100, a carry pulse will appear at theoutput of the first decade 40a of the dividend channel :carry counter 40when the accumulated Vpulse count in the dividend channel equal N 101, acarry pulse will appear at the output of the second decade 40b when theaccumulated pulse count in the divisor channel equals N X102, a carrypulse will appear at the output of the third decade 40C when theaccumulated divisor pulse count equals N X 103, and a carry pulse willappear at the output of the fourth decade 40d when the `accumulateddivisor pulse count equals N 104. For example, if the selector switch38h is set to the position associated with the scaledown factor 7, anaccumulated divisor count of 7 will be indicated by a carry pulse at theoutput of the scaledown counter 38, a divisor count of 70 will beindicated by a carry pulse at the output of decade 40a, a divisor countof 700 will be indicated by a carry pulse at the output of decade 4011,and so on.

When the divisor pulse count, as well as the dividend pulse count, isscaled down in this way, we may rewrite the preceding equations asfollows. In the following equations, the remainder count r remaining inthe dividend scaledown counter 30 is neglected. At the close of acounting interval ending when a carry Ipulse appears at the output ofthe divisor channel scaledown counter 38 or `at the output of any one ofthe decades 40a, 40h, 40C or 40d of the divisor channel carry counter40, the total accumulated pulse count C1 in the dividend count channelwhere R is the reading of the dividend channel carry 4counter and N isthe scaledown factor which is preset into both the dividend countchannel `and the divisor count channel. At the close of the abovecounting interval, the total accumulated pulse count C2 in the divisorcount channel is where n is zero if the count is terminated in responseto the first carry pulse at the output of the divisor channel scaledowncounter 38, l if the count is terminated in response to the first carrypulse at the output of the first carry counter decade 40a, 2 if thecount is terminated in response to the first carry pulse at the out-putof carry counter decade 40b, 3 if the count is terminated in response tothe first carry pulse at the output of carry counter decade 40C, and 4if the count is terminated in response to the first carry pulse at theoutput of carry counter decade 40d. The quotient Q of the two pulsecounts C1 and C2 is then In other words, if the count is terminated inresponse to the first carry pulse at the output of the divisor channelscaledown counter 38 or at the output of any one of the carry counterdecades 40a through 40d, the reading R of the dividend channel carrycounter 32 is the correct numerical value of the quotient of the totalaccumulated pulse count in the dividend channel over the totalaccumulated pulse count in the divisor channel. Thus, when the dividendand divisor counts are scaled down by the same scaledown factor N, allthat is necessary to obtain a correct quotient reading in the dividendchannel scaledown counter 32 is to terminate the count when the firstcarry pulse appears at the output of the divisor channel scaledowncounter 38 or at the output of one of the divisor channel carry counterdecades 40a through 40d. In the illustrative embodiment of the presentinstrument, the decimal multiplier selector knob S0 is preset to causeautomatic termination of the count in response to the first carry pulseat the output of the divisor channel scaledown counter 38 or at aselected decade of the divisor channel carry counter 40. The decimalmultipliers identifying the various positions of the selector knob 50correspond to the various values of the decimal multiplier l0Ilindicated above. For example, if the selector knob 50 is set to theposition identified `by the decimal multiplier 100, the movable contact52f of the selector switch S2 engages contact 52C of the switch so thatwhen the first carry pulse appears at the output of the second carrycounter decade 40h, a control pulse is delivered through the selectorswitch 52 to the input gates 29 and 36 of the counting channels. Asexplained earlier, this control pulse terminates or effects repetitionof counting in the channels. The decimal point indicating lamp switch 72is simultaneously set to energize the appropriate decimal pointindicating lamp 34a through 34e and thereby indicate the position of thedecimal point in the quotient display of the dividend channel carrycounter 32. Thus, `when the selector knob 50 is set to the decimalmultiplier 1, lamp 34a is illuminated. When the knob S0 is set to thedecimal multiplier position 10, lamp 34h is illuminated. When theselector knob S0 is set to the decimal multiplier (position 100, lamp34C is illuminated, and so on.

From the preceding discussion, it is evident that an accumulated divisorcount at which counting will be automatically terminated is preset intothe divisor channel by setting selector knob 46 to a selected integerand setting selector knob 50 to a selected decimal multiplier and thatthe divisor count which is thereby preset into the divisor channelequals the selected integer times the selected decimal multiplier. Thus,in the illustrated instrument, the preset divisor count may numericallyequal any one of the integers 0 through 9 times any one of the decimalmultipliers, 1, 10, 100, 1,000 or 10,000.

Briefly reviewing the operation of the illustrated instrument, a totalaccumulated divisor pulse count, within the range of the instrument,which will afford the desired accuracy of measurement is first selected.The selected divisor count is then preset in the divisor count channelby turning the `selector knob 46 to the selected integer and theselector knob 50 to the selected decimal multiplier. Setting theselector knob 46 simultaneously presets the scaledown factor selectorswitches 301; and 381; to the appropriate scaledown factor for theselected divisor count. Setting the selector knob 50 presets theselector switch 52 to condition the instrument for automatic terminationor repetition of the count, depending on the position of the switch 64,when the preselected count is reached in the divisor channel. Knob 50also presets the selector switch 72 to illuminate the proper decimalpoint indicating lamp 34a through 34e.

As the count progresses in the count channels, the scaledown counter 30in the dividend count channel 20 develops a carry pulse in response toeach Nth count of the counter, where N is the scaledown factorcorresponding to the preset position of the selector knob 46. The carrycounter 32 in the dividend count channel counts and displays the numberof carry pulses developed by the scaledown counter 30. The same eventsoccur in the divisor count channel 22. When the preset total accumulatedpulse count is reached in the divisor channel, a control pulse isdelivered to the input gates 29 and 36 through the selector switch 52and opens these gates to terminate counting in both channels. If switch64 is open, gates 29 and 36 remain open until reclosed by manualoperation of the reset switch 70. If switch 64 is closed, the controlpulse delivered through the selector switch 52 triggers the reset pulsegenerator 62 which then generates a reset pulse for resetting all of thecounters to zero and reopening the gates 29 and 36 to repeat the count.The quotient of the total dividend pulse count over the total divisorpulse count at the end of a counting interval is read directly from thedisplay scales 32f of the dividend channel carry counter 32, as alreadynoted.

When the instrument is used to make a frequency or counting ratedetermination, divisor channel switch 42 is closed to the time intervalgenerator 28 so that the pulses 26 delivered to the divisor channelcomprise timing pulses which occur at preset time intervals, such as .1second intervals. The operation of the instrument is exactly the same asdescribed above except that in frequency or counting rate measurements,selector knobs 46 and 50 are initially set to preset a counting timeinterval, rather than a pulse count, into the divisor count channel 22.Also, in this latter application of the instrument, the divisor channelscaledown counter 38 counts units of time rather than pulses. The carrycount displayed by the dividend carry counter 32 at the end of thepreset counting interval equals the time rate of occurrence of thepulses delivered to the dividend channel, i.e., frequency or countingrate.

Time interval generator 28 may comprise any type of means for generatingelectrical timing pulses at predetermined time intervals. FIG. 2illustrates one type of time interval generator which can be used in theinstrument. This time interval generator comprises a scaledown counter76 which, for simplicity, may be regarded at this point as being of thesame type as the scaledown counters 30 and 38 described earlier.Scaledown counter 76 may be preset with a scaledown factor of 6, forexample, in which case the frequency of the timing pulses generated bythe scaledown counter is 60/ 6 or l pulses per second. In other words,the timing pulses occur at 1/10 second intervals.

When the instrument is used for ratio counting, that is, determining theratio of an unknown frequency f1 to a known frequency f2, the unknownfrequency may be fed to the dividend channel 20 and the known frequencymay be fed to the divisor channel 22. Before the actual count isstarted, knobs 46 and 50 are set to preset a desired count into thedivisor channel and appropriate scaledown factors into the dividend anddivisor channels. Counting is stopped automatically when this presetcount is reached in the divisor channel, as before. The frequency ratiof1/f2 is then where C1 is the total accumulated count in the dividendchannel and C2 is the total accumulated count in the divisor channel atthe end of the count, and T is the time of measurement or counting timeinterval. The time of measurement T is the same in both channels, ofcourse. Recalling that the dividend count C1 equals the reading R of thedividend channel carry counter 32 multiplied by the preset scaledownfactor N in the dividend channel and that this scaledown factor N is inthe ratio of n to the accumulated divisor count C2 when counting isterminated, the above equation becomes where n is the decimal multipliercorresponding to the preset position of the knob 50.

The carry counter reading R is, then, the numerical value of thefrequency ratio. Presetting the knob 50, of course, illuminates theproper decimal point indicator lamp 34a-34e so that the decimal value ofthe ratio may be read directly from the dividend channel carry counter32.

The above method of determining frequency ratios requires that bothfrequencies be available simultaneously.

In some cases, however, it may be difficult or impossible to obtain bothfrequencies simultaneously. For example, when the frequencies whoseratio is to be determined are pulse frequencies in which the pulses arederived from the detection of radioactive emissions from two radioactivesources, only one pulse frequency may be available at any one time dueto the availability of but a single radiation detector. In this case,the instrument must be capable of making the frequency ratiodetermination by rst counting one frequency and then the other.

To this end, the instrument illustrated in FIG. l is equipped with acoincidence pulse generator which is connected with selector switches82a, 82h, 82C, 82d and `82e through lines 84a, 84h, 84C, `84d and 84e.Each selecfor switch has ten positions identified by the integers 0through 9, respectively, as shown. Selector switches 82al82e areelectrically connected with the counting decade 38a of the divisorchannel scaledown counter 38 and with the counting decades 40u-40d ofthe divisor channel carry counter 40, respectively, as shown, so that apulse is delivered from each of the decades 38a and 40u-40d through therespective selector switches 84a- 84e to the coincidence pulseIgenerator 80 each time the displayed count in each decade becomes thesame as the integer associtated with the position of its respectiveselector switch. For example, if switch 82a is set to the integer 3, apulse is delivered from the counting decade 38a through switch 82a tothe coincidence pulse generator `8G each time the count displayed indecade 38a becomes 3. If switch 82a is set to zero, a pulse is deliveredto the coincidence pulse generator 80 each time the decade 38a resets tozero, and so on. The same applied to the other selector switches anddecades.

When the selector switches =82a-82e are set to the same number, such as46531, for example, the coincidence pulse generator 80 will receivepulses from the decades 38a and 41m-40d simultaneously when the count inthe divisor channel becomes 46531. In other words, the pulses from thedecades are in coincidence at the coincidence pulse generator 80. Thecoincidence pulse generator generates an output pulse in line 86 inresponse to this coincidence of the pulses from decades 39a and 40u-40d.A preset counter of this kind which generates a coincidence output pulseat a preset count is disclosed in the previously mentioned Computer-Measurements Company manual.

Now if the scaledown factor selector switch 3811 of the divisor channelscaledown counter 38 is set to zero and switch 42 is set to the timeinterval generator 28, a carry pulse will appear at the output of thescaledown counter 38 at each tenth count of t-he scaledown counter.Assuming that timing pulses are delivered to the scaledown counter at .1second intervals by the time interval generator28, as described earlier,carry pulses will appear at the output of the scaledown counter 38 at 1second intervals and the divisor channel carry counter 40 reads seconds.In this case, then, the divisor channel counters read real time and whencombined with the selector switches `82a-82e and the coincidence pulsegenerator 80 pro'vide a preset timer which generates a coincidence pulsein line 86 upon the expiration of a time interval equal to the number ofseconds which Iare preset in the selector switches 32a-82e.

Coincidence generator output line y86 connects to one contact 88a of amode selector switch 88. Switch `88 has a second contact 88b connectedto the movable contact 52)c of the decimal multiplier selector switch 52and a third contact `88C connected to the Kmovable contact 90a of aselector switch 90, the movable contact 90a of which is fixed to theshaft 56 of selector knob 50. When the instrument is used to determinequotients and counting rates or frequencies in t-he manner describedearlier, switch 88 is closed t0 contact `88h so that the control pulsedelivered through the decimal multiplier switch 52 at the end of a countpasses thro-ugh -rnode selector switch `8S to the Igates 29 and 36 andthe reset pulse generator 62.

Switch 90 is a second decimal multiplier switch having contacts 90b,90e, 90d, 90e and 90j connected to the outputs of the decade 30a in thedividend channel scaledown counter 30 and the decades 32a-32e of thedividend channel carry counter 32, respectively, through lines 92b-92f,respectively, as shown.

From this description and the earlier description relating to theoperation of the decimal multiplier selector switch 52, it is evidentthat when movable contact 90a of switch 90 is engaged with Contact 90b,by rotation of selector knob 50 to the decimal multiplier 1 position, apulse is delivered through switch 90 to the mode switch contact 88C whenthe accumulated dividend channel count equals the decimal multiplier lmultiplied by the preset scaledown factor N in the dividend channelscaledown counter 30. Similarly, when the switch contact 90a is engagedwith any of the other switch contacts 90o-90j by rotation of theselector knob `S to the corresponding decimal ymultiplier 10, 100, 1,000or 10,000, a control pulse is delivered through switch 90 to the modeswitch contact 88e when the accumulated dividend count equals the presetdecimal multiplier multiplied by the preset scaledown factor N in thedividend channel scaledown counter 30.

Mode switch 88 includes a knob 94 having three positions identified bythe legends QUOTIENT, PRESET COUNT and RATIO When knob 94 is set to theQUOTIENT position, -mode switch 8S is closed to contact SSb to conditionthe instrument for quotient and counting rate or frequencydeterminations, as already noted. When the knob is set to the PRESETCOUNT position, the mode switch 88 is closed to contact 88C and when setto the RATIO position, the mode switch is closed to contact 88a.

These two latter positions of the mode switch are used in the.alternative method of ratio counting when the frequencies whose ratiois desired are not simultaneously available, as follows: The mode switch81S is closed to contact 88C by setting the mode switch knob 94 in itspreset count position. A desired count is preset into the dividendchannel by setting the selector knob 46 to the appropriate integer andselector knob 50 to the appropriate decimal multiplier. The samescaledown factor is thereby preset in both channels. Switch 42 is closedto the time interval generator 28. The known frequency or the frequencyfrom which is to be derived the divisor count of the frequency ratiodetermination is then fed to the dividend channel, whereupon counting iscommenced.

When the preset count is reached in the dividend channel 20, la. controlpulse is delivered through switch 90 and mode switch 88 to the -gates 29and 36 -which are thereby opened to terminate counting in the twochannels.

If the repeat switch 64 is closed, counting lwill be repeated, asbefore. At the end of counting, the reading of the divisor channelcounters 38 and 40 is observed. The divisor channel counters will notindicate real time, of course, unless t-he scaledown factor of zero ispreset into the divisor channel.

Selector switches 82a-82e are now setto the same reading as thatobserved on the divisor channel counters and mode switch 88 is closed tocontact 88a by setting of the mode switch knob 94 in its ratio position.After the instrument is thus set, a new count is made by feeding theunknown frequency, or the frequency from which is to be derived thedividend count of the desired frequency ratio, to the dividend channel20. When the elapsed time of counting equals the reading of the presetselector switches 82a-82e the coincidence pulse generator generates acoincidence pulse which is delivered to the gates 29 and 36 through themode switch S8 to terminate the count.

Now it is evident that since the elapsed time of the known or standardfrequency count and the elapsed time of the unknown frequency count arethe same and since the same scaledown factor is used in both counts, theequations set forth in the discussion of the first method of ratiocounting apply as well to the alternative method of ratio counting sothat the reading of the dividend channel carry counter at the end of theunknown frequency count is the numerical value of the frequency ratio.The decimal point is indicated as before.

FIG. 3 illustrates an alternative binary scaledown counter which can beused in the instrument in place of the decade scaledown counters shownin FIG. l. The binary dividend channel scaledown counter comprisesbinary counters 10001, 100b, 100C, 100:1', such as hip-flops, and ascaledown factor selector switch 104 for extracting the carry pulsebetween selected stages. The divisor channel scaledown counter 102 isidentical and comprises binary stages 102:1, 102b, .102C and `102e? anda scaledown factor selector switch 106 for extracting the carry pulsesbetween selected stages. The selector switches are operatively connectedto a selector knob 108 having positions identified by the binary seriesintegers 2, 4, 8 and 16. The incoming pulses to each scaledown counterare applied to the rst stage of the counter and the carry pulse outputfrom each counter is taken from the movable contact of the counterselector switch 104 or 106.

When knob 108 is set to the integer 2, the scaledown selector switches104 and 106 are set to extract the carry pulses which occur between therst and second stages of the respective counters. These carry pulsesoccur, of course, in response to each second incoming pulse to thecounters. When the knob 108 is set to integer 4, the selector switches104 and 106 are setto extract the carry pulses between the second andthird stages of the counters which occur in response to each fourthincoming pulse to each counter. Similarly, when knob 108 is set tointeger 8, the scaledown counters produce carry pulses in response toeach eighth incoming pulse and when set to integer 16, the scaledowncoutners produce carry pulses in response to each sixteenth incomingpulse. The scaledown counters 100 and 102, therefore, provide thescaledown factors 2, 4, 8 and 16.

In use, the scaledown counters of FIG. 3 are inserted in the instrumentof FIG. 1 in place of the scaledown counters 30 and 38 so that the carrypulses produced by the counters 100` and 102 are counted by the carrycounters 20 and 22. The operation of the instrument with the scaledowncounters 100 and 102 is precisely the same as described in connectionwith FIG. 1 except that the permitted scaledown factors are 2, 4, l8 and16 rather than 0 through 9 as in the instrument of FIG. 1. The scaledowncounters of FIG. 3 are superior to those of FIG. 1 in that the countersof FIG. 3 do not require the resetting circuitry which is necessary inthe scaledown counters of FIG. 1.

These two types of scaledown counters are not the only types ofscaledown counters which can be used in the instrument.

Ring counters with means to extract the carry pulses between selectedstages may be used, for example, as well as any other kind of counterwith means to produce a carry pulse in response to preselected numbersof input pulses. The scaledown counters may obviously be based on anysystem of counting.

Other types of carry counters than decade carry counters may also beused in the instrument. For example, the decade carry counters of FIG. 1may be replaced by binary carry counters or by carry counters which arebased on any other counting system. Also, as shown in FIG. 4, the carrypulses produced by the scaledown counters can be counted in a mechanicaldigital carry counter rather than in an electronic carry counter as inFIG. 1.

The range of the instrument may obviously be expanded by adding as manycounting stages as desired to the scaledown counters and/or the carrycounters of the instrument. i

...IMJ

Clearly, then, the invention herein described and illustrated is fullycapable of attaining the objects and advantages preliminarily set forth.

I claim:

v1. A direct readout computer-sealer, comprising:

(a) a divisor count channel including a rst digital pulse counter having(l) a rst input terminal for receiving a rst train of incoming pulses ofunknown frequency, which frequency may be periodic or aperiodic; and

(2) means for generating an electrical control pulse in response to apredetermined accumulated pulse count in said divisor count channelconstituting an integral multiple of n where n is any positive integer;

(b) a dividend count channel including a second digital pulse counterhaving (1) a second input terminal for receiving a second train ofincoming pulses of unknown frequency, which frequency may be periodic oraperiodic, said second train of pulses being wholly independent of saidrst train of pulses;

(2) means for generating an electrical carry pulse in response to eachNth count of said second digital pulse counter, where N is a preselectedinteger equal to said integral multiple;

(3) a digital carry pulse counter for counting said carry pulses; and

(4) means responsive to said electrical control pulse from said divisorcount channel to terminate counting in said dividend count channelwhereby the count displayed by said carry pulse counter in said dividendcount channel when counting is terminated, is equal to 1011 times thetotal number of pulses counted in said dividend count channel divided bysaid predetermined pulse count in said divisor count channel.

2. A direct readout computer-Scaler according to claim 1, in which saiddivisor count channel includes a presettable means to establish saidintegral multiple, said presettable means being coupled to said meansfor generating said electrical carry pulse in said dividend countchannel such that the value of N is simultaneously changed with changesin said pre-settable means to assure that said integral multiple and Nare always equal.

3. A digital readout computer-Scaler according to claim 2, in which saidintegral multiple and value of N may be pre-set to any one of thesuccessive integers l, 2, 3, 4, 5, 6, 7, 8, and 9.

4. A direct readout computer-scaler according to claim 1, includingdecimal point indicating means in said dividend count channel responsiveto the preselected value of n to indicate a decimal point in the displaycount of said carry pulse counter in a position such that the displayedcount equals the quotient defined by the total counts in said dividendcount channel divided by the total counts in said divisor count channel.

5. A direct readout computer-Scaler according to claim 4, includingstorage means connected to said divisor count channel for establishing atime interval equal to the time to complete said predeterminedaccumulated pulse count; and means connected to said storage means forpassing a coincidence signal to said dividend count channel to terminatecounting in said dividend count channel at a time from the start of thecounting of said dividend count channel equal to said time interval,whereby said rst train of incoming pulses may be counted in said divisorcount channel to establish said time interval and at a subsequentarbitrary later period in time said second incoming train of pulses maybe counted in said dividend count channel and thence terminated by saidcoincidence signal whereby the quotient defined by the total count ofsaid rst train of pulses divided by the total count of said second trainof pulses is displayed by said carry pulse counter at the termination ofcounting of said dividend count channel even though said rst and secondtrains of pulses are counted at different times.

References Cited UNITED STATES PATENTS 2,743,419 4/ 1956 Chatterton 23S-92 2,853,235 9/1958 Brinster 235-92 X 3,006,549 10/1961 Hughes 23S-1603,133,189 5/1964 Bagley 23S-92 2,828,468 3/1958 Ball 23S-92 MAYNARD R.WILBUR, Primary Examiner. G. I. MAIER, Assistant Examiner.

